1. Field of the Invention
The present invention relates generally to a sprinkler assembly for controlling a fire situation.
2. Description of the Related Art
Conventional methods of extinguishing chemical reactions such as fire or flames include sprinkler systems. According to the standard for the Installation of Sprinkler Systems, NFPA 13, a sprinkler system is defined as an integrated system of underground and overhead piping designed in accordance with fire protection engineering standards. The installation includes one or more automatic water supplies. The portion of the sprinkler system above ground is a plurality of specially sized or hydraulically designed piping installed in a building, structure, or area, generally overhead, and to which sprinklers are attached in a systematic pattern. The valve controlling each system riser is located in the system riser or its supply piping. Each sprinkler system riser includes a device for actuating an alarm when the system is in operation. The system is usually activated by heat from a fire and discharges a fire-retardant substance such as water over the fire area.
The most common type of sprinkler system is a wet pipe sprinkler system. A wet pipe sprinkler system employs automatic sprinklers attached to a piping system containing water and connected to a water supply so that water discharges immediately from sprinklers opened by heat from a fire. This type of system is the simplest and most reliable. However, in areas where the sprinkler system, in whole or in part, is subject to freezing conditions, water cannot be maintained in the sprinkler system piping since it could freeze and compromise the integrity of the system.
The traditional way of providing fire sprinkler protection in these areas is by the use of an antifreeze system, dry pipe sprinkler system and/or dry sprinklers. Antifreeze systems are wet pipe assemblies that utilize an antifreeze solution in the piping system to prevent a freeze up of the sprinkler system. When one or more sprinklers is opened due to a fire situation, the antifreeze solution is discharged followed by water, which enters the system from a connected water supply. Because an antifreeze system is usually part of a wet pipe sprinkler system, it requires some form of separation from the wet pipe system to prevent the mixing of the antifreeze solution and the water. This is generally accomplished using a special valve and piping arrangement. The antifreeze solution must also be monitored periodically to ensure the proper mixture is maintained. Also, an antifreeze system is subject to regulation by state and local health and municipal water departments. These regulations have placed restrictions on the use of antifreeze systems to protect against contamination of public water supplies. All of these items have an impact on the cost effectiveness of using antifreeze systems, and thus, are disadvantageous.
A dry pipe sprinkler system is one in which water is prevented from entering the sprinkler system piping until a fire situation has occurred. A dry pipe sprinkler system includes a dry pipe valve which is installed between a water supply and piping of the sprinkler system. The sprinkler system side of the dry pipe valve is pressurized with a gas such as air or nitrogen. This pressure holds the dry pipe valve closed preventing water from entering the system. When a sprinkler activates, the gas pressure drops in the sprinkler system. When the gas pressure drops to a level such that it can no longer hold the dry pipe valve closed, the valve opens and allows water to enter the entire piping system. When a sprinkler system is exposed only to local freezing conditions, such as a freezer, a dry sprinkler is typically used to provide fire protection to that area.
The typical construction of a dry sprinkler is a sprinkler head that is permanently mounted on the end of a length of pipe opposite the inlet end of the pipe. A fusible element or frangible glass bulb is located in the sprinkler frame and is in contact with a strut, rod or tube. The strut, rod or tube transfers the force required to hold in place a seal that is located at the inlet end of the pipe. The seal prevents water from entering the pipe until the sprinkler has operated. Some dry sprinkler designs utilize a pressurized gas filled pipe instead of a strut rod or tube to transfer the load to the seal inlet from the sprinkler head. In the event of a fire situation, the fusible element or frangible glass bulb activates, releasing the force holding the seal in place and allowing water to flow through the dry sprinkler pipe and out the sprinkler head.
When the dry sprinkler is installed into the sprinkler piping system, the sprinkler head of the dry sprinkler will be located inside the area where the freezing conditions will occur. The pipe, which makes up the length of the dry sprinkler, is kept dry by the seal located at the inlet of the dry sprinkler. This prevents the pipe from filling up with liquid and freezing. The inlet of the dry sprinkler is connected to the sprinkler piping system. The length of the dry sprinkler can vary depending on the location of the sprinkler system with respect to the location of the head of the sprinkler.
The benefits derived from using a conventional dry sprinkler is based essentially on an economical solution to fire protection of a local area that is subject to freezing conditions without the need for a complete dry pipe sprinkler system. The disadvantages of using a conventional dry sprinkler is that it varies in size and currently is made to order by a dry sprinkler manufacturer. The current manner of installing dry sprinklers is to initially measure the distance from the sprinkler piping system to the locations that the sprinklers will be employed. Subsequently, a list is made of the location and size of each dry sprinkler required for a given installation. An order for these dry sprinklers is then placed with a dry sprinkler manufacturer. Completion of the installation then waits for the manufacturer to produce and send them to the contractor. In essence, the process for installing conventional dry sprinklers is time consuming. In addition, unlike a wet pipe system, the length of a pipe nipple in a dry sprinkler cannot be adjusted in the field by the sprinkler fitter. If the contractor orders the wrong size or the manufacturer fabricates the wrong size, another order must be issued, which further delays the installation time.
An improved assembly and method is, therefore, desired for employing the controlled distribution of a fluid to a selected portion of a fluid distribution assembly that is not only simple, durable, reliable, but also provides effective sensing and extinguishing of fire within a selected zone as well as is economical to build, maintain and operate.